Stars being born in the Orion Nebula. Composite of images from the Hubble Space Telescope, by C.R. O'Dell of Rice University and NASA/ESA.

I’ve been writing a lot about the cardinal T-square of this summer. Well, as of Monday, June 21, summer is here, and the T-square kicks in immediately.

The Sun’s entry into Cancer officially marks the beginning of summer (winter in the Southern Hemisphere). As the Sun moves through the early degrees of the Crab, it will form conflicting aspects with Uranus and Jupiter in early Aries and Pluto in early Capricorn, forming three legs of a triangle pattern, or T-square, made up of cardinal signs. The cardinal signs are characterized by impulsiveness, action, and change. That is why astrologers have been predicting sweeping worldwide changes in 2010 and 2011, when the cardinal T-square and cross will be active.

The 2010 Cancer ingress is all the more dramatic, because it occurs just five days before a lunar eclipse in the same degree as Pluto. Is the world going to end? Of course not. And, chances are, the sky is not going to fall on our heads. As I mentioned in my post on the eclipse, there could be positive developments and breakthroughs for many of us. If you’ve been stuck and in need of a good push, get ready to start moving again.

But I believe it’s safe to say that the next two months are going to bring shocking developments that we cannot imagine now and that thus will be impossible to prepare for. The likeliest time for these events would be at the peak of the cardinal build-up in late July and early August.

However, with the Sun’s entry into Cancer this week, we may start to get some clues. It is no coincidence that most of us identify primarily with our Sun sign. The Sun represents our center, our heart, our core energy. Events in the next couple of weeks will take root in our hearts, and who knows where that could lead?

Shortly after the Cancer ingress, the Sun squares Uranus in Aries. The fires and explosions in the headlines over the past couple of days are possible expressions of this aspect, but Uranus is a wild card and unpredictable. It is safe to bet that whatever happens will be big. That’s because Jupiter, the amplifier, is just a couple of degrees from Uranus. The Sun forms an exact square to Jupiter on Wednesday.

Even without the involvement of Uranus, Sun-Jupiter contacts tend to involve extremes, over-the-top behavior, and recklessness, although they can be very lucky, too. And, while Saturn is still in mutable Virgo, he’s close enough to opposition with Uranus and Jupiter that I am hopeful this will be a stabilizing influence.

You should know by now what areas of your life are being most heavily impacted by this complex configuration. Still, there’s a strong possibility of surprise developments this week.

Mercury, meanwhile, is about to enter Cancer on Friday. As he moves through the last degrees of Gemini on Wednesday and Thursday, he opposes Ceres in Sagittarius, squares Saturn in Virgo, and trines Neptune in Aquarius. More environmental bad news may be on the way, and the dialog intensifies about what it all means and what we can do about it.

After entering Cancer, Mercury squares Uranus and Jupiter, repeating the Sun’s contacts of a few days earlier. If we didn’t get the message the first time around, we’ll have another chance. Events may come in pairs this week.

Both the Sun and Mercury also trine Chiron in early Pisces. The Healer is separating from his conjunction with Neptune but still close enough for the two to signify collective healing on a deep level. I am encouraged by this aspect and believe it is a continuing factor in the cardinal build-up. It’s more of a side issue at this point, but we shouldn’t ignore this influence or let the opportunity pass for healing deep wounds from our past.

Tension will build during the week as we approach the Full Moon lunar eclipse in Capricorn on Saturday. We’re moving into the gravitational pull of the Sun and Moon, and we’re also pulled in several directions at once by an extreme configuration of planets that, as far as we know, has not occurred in recorded human history (if anyone out there can find a date, please drop me an e-mail!).

I wrote a long post on Saturday about this eclipse and won’t repeat myself here, except to say that we’re approaching the rapids and need to hang on tight. Think about who and what constitutes your safety net or personal flotation device.

Just found this insightful and far-reaching analysis of the Solstice by Barbara Hand Clow. It’s well worth wading through, especially for those of you who are interested in the Mayan Calendar. (Scroll down the page to “2010 Summer Solstice: June 21, 2010”).